Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
659 PM EST Fri Jan 27 2023
Valid 12Z Tue Jan 31 2023 - 12Z Sat Feb 04 2023
...Pattern overview and Weather/Hazard Highlights with Model
Guidance/Predictability Assessment...
A highly anomalous upper ridge over Alaska will continue to be
eroded during the medium-range period as additional troughing
associated with outbreaks of frigid air from Siberia work their
way across the North Pacific. Model ensemble means show good
agreement that a piece of the anomalous ridge will retreat into
the Arctic Ocean and become an upper closed High while the main
center of a polar vortex meanders over eastern Siberia. In this
pattern, some snow is expected to linger early next week across
the north-central interior section near a stationary front and
where a break in the upper ridge allows some upper cyclonic flow
to settle into the region. The snow is forecast to gradually
taper off through late week. A lingering low pressure system
centered over the Gulf of Alaska will bring unsettled weather
slowly eastward from the Alaska Peninsula to the southern
coastline and then into the Panhandle through next week.
Precipitation is not expected to be excessive, though the southern
Panhandle should see moderate to heavy amounts of precipitation
Thursday or Friday.
Meanwhile, the Aleutians will see unsettled weather as relatively
weak cyclones/disturbances pass by into the middle of next week.
Models are showing poor agreement on placing these cyclones in the
midweek time frame near and south of the Aleutians but the
associated weather impacts are not expected to be hazardous.
Toward next weekend, model ensembles show decent signals that a
larger scale cyclone will gradually approach the western Aleutians.
Temperature-wise, the streak of above freezing temperatures over
southwestern Alaska should continue into at least next Monday
before a slow cooling trend sets in, bringing temperatures back to
near normal for the entire Mainland by the end of next week.
The WPC Alaskan medium range product suite was primarily derived
from a blend of the 12 UTC GFS/ECMWF/CMC and GEFS/00Z ECMWF/CMC
ensemble means in a pattern with overall near average
predictability. The results are quite compatible with yesterday's
forecast package.
Kong
Hazards:
- Much above normal temperatures across portions of mainland
Alaska, Mon, Jan 30.
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html